Abstract 48P
Background
Sentinel lymph node biopsy (SLNB) in post-neoadjuvant chemotherapy (NACT) has demonstrated a higher false negative rate (FNR) compared to early breast cancer. This might result from a non-uniform pattern of tumour regression in SLN and Non-SLN within the axilla. SLNB can assess SLN alone by itself, but preoperative axillary ultrasound (AUS) can also determine the characteristics of Non-SLN. We studied whether axillary staging in post-NACT patients could be improved by combining AUS and SLNB to reduce false negative cases.
Methods
It was a single-centre, prospective study that was conducted between September 2020 and June 2022. All Post-NACT, clinically node-negative(cN0) patients who were scheduled for surgery were enrolled and underwent AUS. AUS normal node patients underwent SLNB using fluorescein and methylene blue followed by Axillary Lymph Node Dissection (ALND). We evaluated the AUS's Positive Predictive Value (PPV), Negative Predictive Value (NPV) and FNR in cN0 patients. The FNR of SLNB was calculated in patients who had cN0 and AUS normal nodes.
Results
cN0 was found in 62 patients out of 136 post-NACT patients.AUS had PPV and NPV of 90.6% and 76.6%, respectively. The FNR for AUS alone was 19.4% (7/36). Loss of fatty hilum was found to have a PPV of 89.3% and a sensitivity of 70%, making it the most reliable marker of nodal metastasis. Methylene blue allergy was observed in 1 patient. The FNR of SLNB was 8.6% (2/23) for the patients who had been selected for SLNB based on AUS normal nodes.
Conclusions
AUS alone or SLNB alone is insufficient to determine axilla node-negative status and can't omit ALND because each has a high FNR (>10%). If AUS findings are considered for selecting patients for SLNB, it reduces its FNR to below 10% and improves the accuracy of axillary staging in post-NACT patients.
Clinical trial identification
Clinical Trials Registry (India) number- CTRI/2020/10/028337.
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
88TiP - A phase Ib study of HMBD-001, a monoclonal antibody targeting HER3, with or without chemotherapy in patients with genetic aberrations in HER3 signaling
Presenter: Nick Pavlakis
Session: Poster Display
Resources:
Abstract
93P - Efficacy and safety of fruquintinib (F) + best supportive care (BSC) vs placebo (P) + BSC in refractory metastatic colorectal cancer (mCRC): Asian vs non-Asian outcomes in FRESCO-2
Presenter: Daisuke Kotani
Session: Poster Display
Resources:
Abstract
94P - Sidedness-dependent prognostic impact of gene alterations in metastatic colorectal cancer in the nationwide cancer genome screening project in Japan (SCRUM-Japan GI-SCREEN)
Presenter: Takeshi Kajiwara
Session: Poster Display
Resources:
Abstract
95P - Interim results of a prospective randomized controlled study to compare the clinical outcomes of total neoadjuvant therapy vs long course chemoradiotherapy in locally advanced carcinoma rectum
Presenter: Sandip Barik
Session: Poster Display
Resources:
Abstract
96P - Tyrosine kinase inhibitor (TKI) plus PD-1 blockade in TKI-responsive MSS/pMMR metastatic colorectal adenocarcinoma (mCRC): Updated results of TRAP study
Presenter: Jingdong Zhang
Session: Poster Display
Resources:
Abstract
97P - Asian subgroup analysis of the phase III LEAP-017 trial of lenvatinib plus pembrolizumab vs standard-of-care in previously treated metastatic colorectal cancer (mCRC)
Presenter: Rui-Hua Xu
Session: Poster Display
Resources:
Abstract
98P - Real clinical impact of postoperative surgical complications after colon cancer surgery
Presenter: Toru Aoyama
Session: Poster Display
Resources:
Abstract
99P - Extended lymphadenectomy may not be necessary for MSI-H colon cancer patients after immunotherapy
Presenter: Rongxin Zhang
Session: Poster Display
Resources:
Abstract
100P - Identification of phenomic data in the pathogenesis of colorectal cancer: A UK biobank data analysis
Presenter: Shirin Hui Tan
Session: Poster Display
Resources:
Abstract
101P - The coexistence of TP53 gain-of-function mutation and hypermethylation as a poor prognostic factor in BRAF wild-type metastatic colorectal cancer
Presenter: Kota Ouchi
Session: Poster Display
Resources:
Abstract